[Kodhifi]

Quote:

Don't believe everything written on the internet. Besides, how can you test if a child is really listening?

You blindfold them, put headphones on, and look for a reaction. They do it all the time if it's suspected an infant or toddler has hearing problems because they need to catch it early to ensure they compensate so the child will develop normal social skills.
 
I've heard in several areas that infants and toddlers can hear near ultrasonic, I didn't remember any particular source. The point I was making was there is nothing hardwired in our brains to correspond to 20-20khz and if there were do you really think it would be exactly those frequencies in nice round numbers?
 
And I was talking of the general population. There are always a small percentage of abnormal cases who have extra perception. For instance it's been found that about 5% of the population can see extra colors the rest of us cant. If you were one of these people how would you know? An apple looks red to me but what if it looked purple to somebody else but they learned the name for that purple color was red? We can't assume everyone else experiences the world the same way as the average person.
 
Anyway that is getting into side tracked, tangents and minutia.
 
 
I don't consider myself the kind of audiophile some of the people here are, with $5,000 headphone amps and the like, and unless I had FU money I probably wouldn't buy anything like that, but if I had the chance to get a surgery that would let me hear perfect audio, I would mortgage my house to get it. And I wondered, with the other sacrifices audiophiles make to portability, ease of use, and financial for their hobby, if they are as hardcore about it to go under the knife.
 
 
I don't know about the minds limits for frequency but I suspect it will be well beyond what our ears are capable of. Now there are other areas where our brain is definitely the limiting factor. Phase is the best example of this, but we have a mamilian brain, and so do whales, dolphins, and bats, and they can all do echo location/ultrasonic sonar, by mesuring phase and slight delays between ears at a much faster time scale than our own hearing.
 
Humans can't hear in stereo under water for instance. The difference in delay between a sound hitting one ear and then the other is so small because of the speed of sound in water, that our brain gives up and it just seems to come from everywhere. Dolphins and whales can though and it's probably not because of any mechanical limits in our ears, but a limit in our processing of the sound in the brain.
 
Regarding nerve stimulation, it would require electricity at a very small voltage, not chemicals. You can stimulate muscles to move electrically with small voltages on the nerve (not talking about high voltage physiotherapy equipment that shocks the muscle tissue directly). The outside device would use something akin to near field to send electromagnetic energy, and information to the implant.
 
There would naturally have to be many safety precautions to prevent over stimulation of the nerve, etc. I'm not sure about the ear implants, but the corneal implants they are using for blind people are a chip that connects directly to the optic nerve, and it restores the ability to see light and dark to completely blind people. That is a chip interfacing directly with a nerve, and it's already out there today.
 
 
 
 
This whole thread is kind of a thought experiment and the idea of surgically giving people super human hearing was just one tangent.

 

[R-Audiohead]

Quote:

 
 
Regarding nerve stimulation, it would require electricity at a very small voltage, not chemicals. You can stimulate muscles to move electrically with small voltages on the nerve (not talking about high voltage physiotherapy equipment that shocks the muscle tissue directly). The outside device would use something akin to near field to send electromagnetic energy, and information to the implant.

It does this superficially via changes in charge balance causing sodium and potassium channels to open and thus cause an action potential that allows nuerotransmitter release at a motor end plate.
 
This is better described as an "all or nothing" type mechanism however.
 
The installed unit would essentially be using charged substances to open sodium/potassium channels in a specific manner.  The methods you just referenced cause a charge imbalance over a relatively large area and a continuous action potential.  Sure, you can pulse the unit, but sound happens pretty fast.  Also, this method is not nerve specific and causes a charge imbalance over a pretty wide area.  Many sensory nerves exist in the face

 

[musical-kage]

Quote:

..........I feel like you are trying to screw over your own argument there. 
 
The human brain is capable of hearing frequencies much higher/lower than what our ears can process. The fact that we can't hear x.y.z frequency is because our ears go bad after a while. 
 
If you had a neural implant, then you are bypassing the ear and the only bottle neck would be the human brain, and god only knows what kind of frequencies we could possible process. 
 
It is kind of like the same thing with human sight. Our brain can process light frequencies far beyond what our eyes can pick up on. If you bypass the eye and rely on the brain, some scientists believe we could see in infrared. 

There are a few cases I've read about where people with a certain eye condition can see ultra-violet light, so its not completely out of the question

 

[musical-kage]

Quote:

I miss being able to hear 21khz and even higher. I could just a few years ago, 19 now. I can still hear 10hz on some good IEMs. But the older you get the less you can hear. All these background sounds that are part of the recording itself, specifically the high pitched ones, I won't be able to hear some day. That sucks pretty hard. I never got why people said humans can't hear below 20hz, I most certainly can.

Most audio equipment only outputs at 20hz-20khz. The headphones themselves if they are good can go lower, but that is only to make sure they will be able to produce the 20hz-20khz as cleanly, and with a lot going on as possible.
So, it could be a case of your audio source not being capable to produce 20hz very well, and so if trying to go lower, you are just hearing a bad signal since your headphones (as an example) can't go down that low, and your audio source can't output less than 20hz.

 

[Kodhifi]

I'm glad you brought up what audio equipment is capable of. Even with DAC's it is possible to produce well below 20hz with standard audio equipment. I use a sine wave sweeper and I can clearly hear bass extending down to 10hz and lower although below 10 it's more like the air itself is shuddering, outside sounds take on a pulsing, distorted quality.
 
This is possible because all you need to effectively sample a particular frequency of sound is to double it. For instance the standard of 44.1khz could theoretically go to 22khz audio, but they give it that extra headroom to prevent DAC noise as the conversion of analog to digital often results in a lot of higher order harmonics and noise so it's either filtered, oversampled, etc to compensate.
 
That means all you need to sample a 10hz wave form is a 20hz sample rate.
 
It's also been said that below 30hz we mostly hear with our bodies and bone conduction, yet here I was earlier tonight with sony V6's clearly hearing 10hz bass at a moderate listening level. Go figure.
 

 

[obobskivich]

I'm glad you brought up what audio equipment is capable of. Even with DAC's it is possible to produce well below 20hz with standard audio equipment. I use a sine wave sweeper and I can clearly hear bass extending down to 10hz and lower although below 10 it's more like the air itself is shuddering, outside sounds take on a pulsing, distorted quality.

This is possible because all you need to effectively sample a particular frequency of sound is to double it. For instance the standard of 44.1khz could theoretically go to 22khz audio, but they give it that extra headroom to prevent DAC noise as the conversion of analog to digital often results in a lot of higher order harmonics and noise so it's either filtered, oversampled, etc to compensate.

That means all you need to sample a 10hz wave form is a 20hz sample rate.

It's also been said that below 30hz we mostly hear with our bodies and bone conduction, yet here I was earlier tonight with sony V6's clearly hearing 10hz bass at a moderate listening level. Go figure.

 

I would guess you were hearing THD or "folding" - not actually 10hz as a pure wave. I say this because, well, a lot of sources would disagree with your superhuman claim. Including measurements of the V6. Sure, it's plausible, but infrasound is generally impossible for headphones to reproduce at any usable level (and it's risky to attempt it in general).

 

[Kodhifi]

Can only tell you my experience, not how it works. 18hz sounds like the trash truck that comes every Friday. 10hz sounds like the wind blowing in a place I used to smoke that would make the whole smoking area shudder as it resonated. Sounds pretty true to real life. Nothing super human about hearing low frequencies.
 
 
I'm trying to think of a way to visually demonstrate it. My SPL meter is weighted for higher frequencies and I doubt it would pick up low frequency very well. I am thinking of wrapping my cans around a glass of water and trying to make ripples with sub bass sounds. Or I could wrap my headphones around my condenser mic and show the signal coming in to my workstation, you should be able to pretty clearly see the wave form and the sound meters moving when I turn the sub bass off and on.
 
 
EDIT
 
Sorry, 15hz was the lowest I went, not 10. I was looking at the slider, not the numeric display.
 
Video to be posted shortly, clearly showing the waveform as recorded by my Blue Yeti condenser mic.
 
 
Youtube video demonstrating 15hz and 18hz subsonics on Sony MDR-V6 with Blu Yeti condenser. http://youtu.be/Zy-g6wGb5zA
 
It's uploading now and will be live shortly.

 

[obobskivich]

Can only tell you my experience, not how it works. 18hz sounds like the trash truck that comes every Friday. 10hz sounds like the wind blowing in a place I used to smoke that would make the whole smoking area shudder as it resonated. Sounds pretty true to real life. Nothing super human about hearing low frequencies.

 

I'm trying to think of a way to visually demonstrate it. My SPL meter is weighted for higher frequencies and I doubt it would pick up low frequency very well. I am thinking of wrapping my cans around a glass of water and trying to make ripples with sub bass sounds. Or I could wrap my headphones around my condenser mic and show the signal coming in to my workstation, you should be able to pretty clearly see the wave form and the sound meters moving when I turn the sub bass off and on.


EDIT

Sorry, 15hz was the lowest I went, not 10. I was looking at the slider, not the numeric display.

Video to be posted shortly, clearly showing the waveform as recorded by my Blue Yeti condenser mic.

I'm not saying the driver isn't making noise, but I'm saying that you're probably listening to distortion from the driver - 10hz is absolutely into the range of infrasound, and is more felt than anything else. The V6's measurements disagree with them being able to produce that at a usable level and I'd be surprised if they could sustain it without damage. As far as using the SPL meter or mic - guessing that won't work either, for the reasons you've highlighted - the mic won't be very sensitive down there.

Regarding perception of infrasound, yes, you can hear pure sine sweeps below 20hz at VERY high output levels (hence why I'm saying the headphones would likely be damaged), but not substantially below - eventually you will just perceive the pressure wave (either on the eardrums or against your entire body, depending on what's generating the wave). The air is still being displaced after all. But in terms of intelligible musical material at 10hz or whatever else - not buying it. Generally listening to infrasound sweeps can produce feelings of nausea, uneasyness, anxiety, and so on - it's not a comfortable experience is basically my point. There's a reason the DOD is interested in this stuff. h34r: And again, this doesn't really matter for music or cinema reproduction because content doesn't really exist down there - sure there's a lot of HT guys who will talk your ear off about how important "20hz flat" and so on is, but it's usually a lot of obsession over a very little thing (30hz is a good lower bound for "full range" reproduction).

As far as the Yeti showing you anything, the manufacturer lists an inaccurate 20-20k spec for the mic (it's not bound or properly formatted so it doesn't tell us anything, unfortunately; I was hoping for a published FR graph (and without a specific calibration file for your mic, your guess is as good as anyone's what you're actually measuring)), but I'm guessing either the ADC or mic itself will not have usable response down around 10hz (and remember that a lot of software sampling engines, codecs, and so on will impose a gate at around 20hz as well). Again, the drivers probably are being moved, but it's very hard to say they're actually giving you a clean 10hz (or 15hz) sine wave output. Should still be interesting to see whatever you get.

Have you tried a pure-sine sweep from say, 20hz up to around 200? Here's an example for you: http://www.audiocheck.net/soundtests_headphones.php (the first item on the list). At a normal listening volume, roughly where do you start hearing the low-end? According to measurement data on the V6, it should be somewhere around 30-40hz. I'd also say walk them through this: http://www.audiocheck.net/testtones_subwooferharmonicdistortion.php

Tyll's measurement data (http://www.innerfidelity.com/images/SonyMDRV6.pdf) show a huge distortion rise (especially at high levels) on the V6 as you move into LF, coupled with an overall LF roll-off. FWIW.

 

[Kodhifi]

I would need a calibrated head analog to properly do a frequency graph of the headphones, this was very unscientific but it does clearly show the wave form being picked up as I generated it from the headphones. It was at a much lower level than say 25hz, but still plainly audible at normal levels and in a somewhat quiet room with computer fans and an air purifier going a few feet away.
 
I know harmonics and artifacts when I hear them and this is not what I'm hearing. I hear smooth bass sweeping down to the level of a large diesel motor idling, hence the trash truck analogy. I can hear that thing coming 1/2 mile away unluckily because of the acoustics of my bedroom. It's one huge bass trap and the room is sympathetic to low frequencies, it's why I have to use a high pass when I'm doing any serious recording work in here. I usually work in my studio but it's nice having another station in my bedroom where I can chill out and mix tracks.
 

 

[obobskivich]

Okay I see what you're talking about - I'm noticing that the waveform is inconsistent though (it isn't a perfect sine wave, at least it doesn't look like it on the video). The other thing I'm wondering here - some DAWs will just spit out the same frequency above or below a certain point (it looks like you're using SoundForge though, which afaik shouldn't do that until you get to the Nyquist limit) - "folding" - just making sure that isn't happening (and it may not be in the DAW software, it may be the output DAC or similar - like the poster who started this discussion said, not a lot of attention is paid to these ranges in equipment design and so on). How high up do you have the input to these, and how shallow is this relative to normal listening? Just thinking about it, I can get my bassiest closed headphones to gargle and rumble at 20hz and thereabouts (and they measure as being able to do it) but it's nothing like "the real thing" (from a sub) with the level turned up sorta high. It's more of a "pressure sensation" than a "I can clearly hear this as a distinct sound" sensation.

Again, certainly *something* is happening, but I'm curious more about the "what" now...


ALSO - I'm laughing at the "Youtube related videos" to that link - apparently "subsonic" means "conspiracy nutjob" because I'm getting a lot of crazy suggestions now ("the truth about alien invasions" and stuff like that).

 

[Kodhifi]

The microphone was about 2 feet away from my head while I was recording and you can see the level of my voice relative to what the headphones are putting out. I had the E9 on low gain and volume knob at about 1/3 which is low to mid volume but not loud. The gain on the mic was neutral and set to the level I usually sing at to get room acoustics (dirty) without clipping.
 

 

[obobskivich]

The microphone was about 2 feet away from my head while I was recording and you can see the level of my voice relative to what the headphones are putting out. I had the E9 on low gain and volume knob at about 1/3 which is low to mid volume but not loud. The gain on the mic was neutral and set to the level I usually sing at to get room acoustics (dirty) without clipping.

 

Yeah I could see the voice bouncing the signal - so I'm guessing this is pretty minimal/soft sounding when on your head?

 

[thoughtcriminal]

I would absolutely go for this. I welcome the idea of enhancing my body cybernetically. There are so many limitations to our bodies and we simply aren't evolving fast enough biologically